Interpolymers of vinyl chloride, higher alkyl acrylate, and divinyl aryl hydrocarbon



Patented Aug. 26, 1952 INTERPOLYMERS OF VINYL CHLORIDE,

HIGHER ALKYL ACRYLATE, AND n1- 7 VINYLARYL nrnRooA Bo Robert J. Wolf, Cleveland, Ohio, assignor to The" A B. F.'Goodrich Company,'New York, N. .Y., a

corporation of New York -No Drawing. Application April 25, 1950, Serial No. 158,063

il'he present invention Claims. (Cl. 260-805) relates to interpolymers obtained by the polymerization of monomeric mixtures containing at least three monomeric components, each in particular proportions, one of-,-which','is. viny1 chloride, anothercf which is a higher alkylacrylatesuch as an octyl acrylate, andganother OfLXVhiCh is a divinyl arylhydrocarbon such: as divinylbenzene, which interpolymers possess;jvarious new, and improved properties, especially in regardto their inherent plasticity and ease of. processing combined with hardness andexcellentstrength. in final end use, and it pertains particularly to three-component intererties in the final product and which,., onjtha polymers or tripolymers of these three types of monomers which areso inherently plasticized in nature as, to be processed and made into excellent films,;sheets, rods, tubes and, plates without the addition of plasticizers.

Vinyl resins such as polyvinyl chloride and copolymers of vinyl chloride with various other monomeric materials such as methyl acrylate,

vinyl acetate, vinylidene chloride and others are well known to the art and in their plasticized {forms are widely used in numerous applications.

The thermoplastic vinyl resin is itself relatively hardand horny at normal temperatures and is generally incapable of being easily subjected to processing operations such as milling, calendering, .extruding, etc., without heating the resin 7 to h ghtemperatures, Addition of plasticizers, whieh generally are of the oily ester type, lowers the softening point ofthecomposition such that the, processing operations may be carried out at end product will have the many-times desirable properties of hardness, rigidity,etc.

If here are additional disadvantages necessarily.

attending the use of plasticizers in vinyl resin compositions. The plasticizers commonly em: ployed have a, pronounced tendency to bleed or migrate'to the surface of the composition, where they are lost through wiping, washing or volatilization with the result that the composition gradually stiiiens and hardens and consequently fails in service. Moreover" the migration of plasticizer destroys! the adhesive bonds between the plastic. and other;surfaces and mars varnished surfaces incontactiwiththe'plastic. 1 a M It is a primary object of this invention, therefore, to provide a new class of vinyl resins each member of which is possessed of many of the I desirable properties of known'vinyl resinsbut whichisso inherentlyprocessable as not to require the addition of plasticizerseitherj ri g processing or to achieve desirable plast account, can be employedto producenum erou's articles which are more durable,serviceableandj otherwise desirable, Another object is to provide a vinyl plastic which is, not subject to loss 'oif plasticity by volatilizationbleeding or extraction of plasticizer. It is also an object to providenew} vinyl resins'which are easily subjected to prop l essing operations at moderately elevated tem-HI, peratures yet which arenot excessively s oft or tacky and have desirable stiffness, rigidity and 1 high strength atnormal temperatures; The at tainment of these and other objectswill. b'e-Y. come readily apparent in the description of the" invention which is to follow.

I have discovered that by polymerizing, prelerably in an aqueous medium, monomeric mixtures containing at least three components, each in definite proportions, onebeing vinyl chloridegg' another a higheralkyl ester of acrylic'acid' such as an "octyl acrylate, and the third a divinyl aryl' hydrocarbon, as hereinafter defined, I am able to' obtain novel interpolymers having the propertiesnecessary for achieving the above andpthelf, 7

objectives.

The relative are employed in the production of my interpoly g mersare somewhat critical, since the desired may vary within certain limits.

ride; from 5 to by weight of higher alkylacrylate, and: from 0.01 to 5.0% by weight or divinylaryl hydrocarbon with at least by} weight of the monomeric mixture made up of thesethree types of ingredients. Other monomeric materials such as vinylidene chloride, di- 3 'ethyl fumarate, vinyl benzoate, acrylonitrile, Sty- 1 rene, isobuty1ene,- lower alkyl acrylatestsuchgas methyl and ethyl acrylate, and others are, if de sirable, utilized to the extent of 10%;by weight 3 of the monomeric mixture without substantially affecting thedesirable properties Particularly; valuable are those interpolymers or tripolymers..-. madefrom three component monomericrmixflj tures containing from 50 to .85 parts bylweight of vinyl chloride, from 15 to 50 parts pr higher alkyl acrylate, and from'0.'1 to 2.0 'parts'by weight of divinyl aryl hydrocarbon.

proportions of monomers whie The higher alkyl acrylates which are employed in this invention are those alkyl esters of acrylic acid in which the alkyl group contains a chain of from 5 to carbon atoms. I have found thatthe degree of plasticity or inherent processability imparted to my new interpolymers by these higher alkyl acrylates corresponds roughly with the observed degree of plasticization imparted to ordinary vinyl resins by addition thereto of ester type plasticizers containing similar alkyl groups. 'For example, di-2-ethylhex-yl phthalate is an excellent plasticizer for vinyl chloride polymers and Z-ethylhexyl acrylate has been found to produce interpolymers possessing inherent processability to a high degree. trative higher alkyl acrylates within the above class utilizable in this invention include n amyl acrylate, n-hexyl acrylate, the isohexyl acryl'at'es,

isoheptyl acrylates, n-heptyl acrylate, capryl acrylate (l-methylheptyl acrylate), n-octyl' acrylate, Z-ethylhexyl acrylate, isooctyl acrylates such as---6' n1thylhexyl acrylate, n-nonyl acrylate, iso. norlyl- -acry1ates such as 3,5,5-trimethylhexyl acrylate, -ndecyl;acrylate and others.

It greatly preferred to employ higher alkyl acryiatea in; which the alkyl group contains a total -of}? to 10 carbon atoms and possesses a carb n' chain of 6 to 10 carbon atoms. Compoundswithin this class are fi-methylheptyl' acrylate; 3f,5',5-trimethylhexyl acrylate; 2-ethylhexyl acrylate, capryl acrylate, n-octyl acrylate, and others. This preferred class of higher alkyl acrylat'e'shas been found to imparta high degree ofinherent'processability to the interpolymers of thr invention andn-octyl acrylate appears tobe themostefiicient in thisrespect.

'I'he divinylaryl' hydrocarbons utilizable in the-production of mynew, interpolymers are any of theipolymerizable aryl hydrocarbons possesslngi twoyinyl' latex of theinterpolymer in the production of the final product. It is preferred to carry out the polymerization inan aqueous emulsion, which may or may not contain an added emulsifying agent, when an aqueous polymeric dispersion is the desired end product. When an'interpolymer is desiredfor the production of clear transparent sheetsand'films, it may be preferred to polymerizeithe mixture of monomers in an aqueous medium conta ming every small amount only of an 'emulsifier or none at all, such method being asoapless? polymerization reaction. In addition -the mixture of monomers may be polymerized-in 'an'aqueous medium containing a colloidal protective substance. such as. gelatin, 'bentonite clam, polyvinyl alcohol, polyacrylic acid, and otli'ei's'to obtaina fine. granular or pearl-like;

IlIus-- lA-divinyl' polymer. The latter aqueous suspension method is a satisfactory method for producing polymer intended to be processed directly in solid form. The mixtures of monomers also may be polymerized in a suitable solvent or in mass in the absence. of a solvent or diluent.

Whatever method of polymerization is employed a catalyst is generally required. The catalyst may be any of the catalysts commonly employed for the polymerization of vinyl compounds. Actinic radiation may be employed, as well .as the various peroxygen compounds such as hydrogen peroxide, benzoyl peroxide, o,o-di- 'chlorobenzoyl peroxide, caproyl peroxide, caprylyl peroxide, pelargonyl peroxide, cumene hydroperoxide, tertiary butyl hydroperoxide, 1-

hydroxycyclohexyl hydroperoxide, tertiary butyl diperphthalate, tertiary butyl perbenzoate, sodium, potassium and ammonium persulfate, sodium perborate, sodium percarbonate, and others. The various peroxygen catalysts may be utilized in combination with a reducing; substance such as a polyhydroxy phenol, sodium sulfite and the like in what is commonly referred to as a redox polymerization- Both the oxidiz ing and redox catalysts reach their full'est" ac-'- tivity when used in combination with aismal'i amount of a heavy metal salt such as silver 'nitrate, copper sulfate, various ferric salts; etc.

In some instances it also may be desirable to control or adjust the hydrogen ion concentrationof the polymerization mixture, which tends to become more acid because of: liberation of'hy drochloric acid during the polymerizationf'It' is preferred therefore to add a buffering sub For this'pur pose. such substances as sodium bicarbonate, so dium carbonate, disodium phosphate, trisodium" phosphate, ammonium hydroxide, sodium fly-*- stance to the reaction mixture.

droxide, the amino -substitutedalcohols such as 2-amino-2-methyl-1-propano1 and the like and others are suitable.

When the monomeric mixture is polymerized: in aqueous emulsiona wide variety of emulsifying agents may be utilized. Suitable materials are for example ordinary soaps such as sodium oleate, potassium palmitate, sodium myri'state,

ethanol-amine laurate, and rosin and' dispropor tionated rosin acid soaps; synthetic saponaceous materials such as the salts of alkaryl sulfonicacids, or of'acid sulfuric'esters of'long chain a1-- cohols such as sodium isopropyl naphthalenesulfonate, sodium lauryl sulfate, and the sodium salts of sulfonated petroleum fractionsand others:

While: the polymerization may be carried out under an atmosphere containing air or oxygen, the, rate ofireaction is: ordinarily faster underan atmosphere substantially freeof oxygen and hence polymerization in an evacuated Vesselbf under an inert atmosphere is preferred, The temperature at which "the reaction is carried-out" is not critical, it may be varied widely from 30? C. to C. or higher, though best results are generally obtained at a temperature in of-0'C. to'70 C.

In order to minimize variation in the-rated? reaction and tomaintain a given proportion 01 each of the three types of monomers in thereaction mixture, throughout the times desirable to therange" The preparation of the interpolymersof this, invention,,;their properties and representative uses will be more clearly described in the following specific examples which are intended merely as illustrations of the natureofymyiin vention and not as limitations on the 1 scope'e thereof.

Example 1 Material Vinyl chloride a. 2-et 1ylhexy1 acrylate 1,4-divinyl benzene. Emulsifier Ammonia 1A sodium salt of a sulfonated petroleum fraction known as Duponol 189 S.

The Water, potassium persulfate and emulsifier are charged to the reactor which is then sealed and evacuated. The ammonia and monomers are then added and the resultant mixture agitated and heated to 50 C. In hours and 20 minutes at 50 C. the reaction proceeds to substantial completion with the production of a latex containing in excess of 50% total solids. The latex when cast on a clean surface and dried at room temperature forms a good clear film. When such a film is heated for 10 minutes at 135 C. an excellent clear film is obtained having a tensile strength of 2670 pounds per square inch and an elongation of 140%. The finished film is clear, dry and tack free and has remarkable resistance to heat aging as shown by no change in properties after heat aging for '7 days at 100 C.

The solid tripolymer derived from the coagulation of the tripolymer latex of Example 1 is easily milled without plasticizer on a mill having the rolls maintained at only 160 F. When the solid tripolymer is press molded without plasticizer for 1 minute at 140 C. a clear, completely fused disc is produced. The hardness of the press molded sheet of trioplymer is 95 Durometer A. The tripolymer is easily extruded without plasticizer to form hard rigid tubes and rods.

Tripolymers made in a similar manner utilizing monomeric mixtures containing respectively 2%, 4% and 5% of divinyl benzene basedon the total weight of monomers are progressively harder and stiffer in nature, yet can be processed without plasticizer.

Example 2 A monomeric mixture consisting of 55 parts by weight of vinyl chloride, 35 parts of 3, 5, 5-trimethylhexyl acrylate, 10 parts by weight of styrene and 0.5 part by weight of 1,4-divinyl benzene is polymerized in aqueous emulsion in the manner of Example 1 to produce an excellent stable latex. The solid tetrapolymer obtained by coagulation of such latex, when molded for 3 minutes at 140 C. forms a completely fused, clear and flexible disc having good heat and light repapersleather, fabrics, etc.

sistance. and which is otherwisesi ilar to th tripolymer of the previous example; Examples A mixture consisting 11 5 parts b y tagttjqr vinyl chloride, 30 parts byweight of Z-et-hylhexyl acrylate, ,5 parts by weight of isobutyleneand 0.1;;

part {by weight of 1, -divinyl} benzene is, poly,- meri zed as in Example 1 in 38% hours .at2 0., to form an excellent latex whichdepositsa c ar m 9 d i t r a m atu an hite isad irably adapted to the formationoficoat Example The interpolymers of this invention can be made with considerable variation, within limits, in the amount of vinyl chloride and higher alkyl acrylate employed. For example, a tripolymer made, as in the previous examples, from a monomeric mixture containing only 35% by weight of vinyl chloride, 64% by weight of isononyl acrylate and 1% by weight of 1,4-divinyl benzene has exceptional processability without plasticizers yet is not excessively soft at room temperature. Another tripolymer made by the polymerization in aqueous emulsion as in the preceding examples of a monomeric mixture consisting of parts by weight of vinyl chloride, 20 parts by weight of n-octyl acrylate and 0.5 part by weight of 1,4- divinyl benzene is a hard rigid resin at room temperature yet is easily milled on a two roll plastic mill having its rolls maintained at only 160 to 170 F. The tripolymer may be calendered on a four roll calender having its rolls maintained at only 200 F. to produce a clear but stiif film of about 10 mil thickness which is admirably adapted for food packaging and the like.

The substitution in the previous examples of 1,4-divinyl naphthalene or 1,2-divinyl benzene for 1,4-divinyl benzene produces generally equivalent interpolymers varying only slightly in hardness but which like the interpolymers of the previous examples also are easily processable without plasticizers.

While the invention has been described with particular reference to certain preferred embodiments thereof, it is possible to make variations and modifications therein without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. An interpolymer made by polymerizing a mixture of monomeric materials comprising from 50 to by weight of vinyl chloride, from 15 to 50% by weight of an alkyl ester of acrylic acid in which the alkyl group contains from 8 to 10 carbon atoms and possesses a carbon chain of from 6 to 10 carbon atoms in length, and from 0.1 to 2.0% by weight of a divinyl aryl hydrocarbon possessing two vinyl groups attached to nuclear carbon atoms ,at least by weight of the said monomeric mixture being composed of the enumerated monomeric materials.

2. A tripolymer made by polymerizing in aqueous emulsion a mixture of monomeric materials consisting of from 50 to 85 parts by weight of vinyl chloride, from 15 to 50 parts by weight of an alkyl ester of acrylic acid in which the alkyl group contains from 8 to 10 carbon atoms and possesses a carbon chain of from 6 to 10 carbon atoms in length, and from 0.1 to 2.0 parts by weight oflA-divinyl benzene.

3. A tripolymer made by polymerizing in aqueous emulsion a monomeric mixture consisting of 50 tq 85 parts by weight of vinyi ch1oride,. from 1 5 imparts by weigkn; of z-ethylhexyl acrylate, and from- 0.1 tb' 2.0 parts byweightof 1,4-diviny1 benzene.

4. An interpolymer made by polymerizing in aqueous" emulsion a monomeric mixture comprising te--'9'5'%' by weight of vinyl chloride;

from 5" t0 65% by'wei'ghi'j of 3,5,5 -trimethy1hexy1' acryl'ate; and from 0.01 to 5.0% by weight of l,4-

divinyl benzene;

1,4-diviny1 benzene.

ROBERT J; WOLF;

REFERENdES CITED Tlie' folIowing' references are of recofd the fiI'e. of this patent:

UNITED" STATES PATENTS Number Name Date 1 2,202,846 Garvey'et all J1me 4,1940 224965384 Nie Feb. 7,1950

OTHER-REFERENCES:

Rehberg era-all Ind; Eng; IQ-1429 33.- (Aug..1948-)5. 

1. AN INTERPOLYMER MADE BY POLYMERIZING A MIXTURE OF MONOMERIC MATERIALS COMPRISING FROM 50 TO 85% BY WEIGHT OF VINYL CHLORIDE, FROM 15 TO 50% BY WEIGHT OF AN ALKYL ESTER OF ACRYLIC ACID IN WHICH THE ALKYL GROUP CONTAINS FROM 8 TO 10 CARBONS ATOMS AND POSSESSES A CARBON CHAIN OF FROM 6 TO 10 CARBON ATOMS IN LENGTH, AND FROM 0.1 TO 2.0% BY WEIGHT OF A DIVINYL ARYL HYDROCARBON POSSESSING TWO VINYL GROUPS ATTACHED TO NUCLEAR CARBON ATOMS AT LEAST 90% BY WEIGHT OF THE SAID MONOMERIC MIXTURE BEING COMPOSED OF THE ENUMERATED MONOMERIC MATERIALS. 